Organic electroluminescent elements (hereinafter also referred to as “elements” or “organic EL elements”) emit light at a high brightness and at a low drive voltage and have therefore been the subject of active research and development. An organic electroluminescent element has an organic layer between a pair of electrodes, electrons injected from the cathode and holes injected from the anode are rebonded at the organic layer, and the energy of the excitons thus produced is utilized to emit light. Organic electroluminescent elements can be provided as elements having a variety of emission wavelengths and are expected to find use in a wide range of applications because they have high response speed and are relatively thin and lightweight. In particular, the development of an organic electroluminescent element with high color purity and high luminous efficiency is important in applications to full-color displays and so on, and various research and development results have been reported up to now.
It is described in Patent Document 1 that the use of materials in which rings are formed from pyrene or other condensed ring structures by single bonds or methylene chains or the like as the fluorescent material makes it possible for the element to emit light in the blue region and to have a long service life. In a working example in this literature, three kinds of compounds are used as blue dopants, and Table 6 indicates that the chromaticity is approximately (0.14, 0.16) and that the maximum efficiency is approximately 7.8 cd/A.
Moreover, it is described in publicly known document 2 that the use of a molecule formed by the expansion of condensed rings of benzofluorene as a light-emitting material makes it possible to obtain a high-efficiency element with a wide gap (that is, blue light emission may also be conceivable). The spectrum of a produced element is disclosed in a working example of this literature, showing that the wavelength was also long, it had a broad waveform, and its maximum emission wavelength was an average of approximately 462 nm.